Embodiments of the inventive subject matter generally relate to the field of high-speed signaling and circuit boards, and, more particularly, to high-speed signaling via multiple circuit boards.
Printed circuit boards (PCBs) include electronic components (e.g., processor chips, memory modules, etc.) with multiple input and output leads. The multiple leads need to be connected to other electronic components, such as other processor chips, via wiring, or conductive wires, that are formed onto the PCB. Some PCBs, or portions of PCBs, may have a dense number of wires connecting a dense number of leads for multiple electronic components. For example, some PCBs include multiple processors that connect to each other. Each of the processors needs to communicate with other processors, usually at very high speeds. However, because the PCB includes multiple processors, the placement of the processors, and their spatial configurations on the PCB, create challenges in connecting the wires for the processors together on the PCB. One such challenge is that the spatial configuration of the wires becomes very crowded when many electronic components need to be connected. The crowded wires produce background noise or cross-talk that interferes with each other's signals. Another challenge is that because of the limited space for the wires, the wires need to be very small. The small size of the wires results in signal attenuation quickly over only a short distance.
Some PCB designers have developed specific configurations for wires on a PCB. Some conventional configurations can, at best, provide high-speed, single-ended signaling at only very short distances (2-3 inches). When the wires increase in length beyond the short distances, cross-talk and signal attenuation significantly interfere with signals on the wires. Thus, as designers place on a PCB more electronic components that need to communicate with each other, PCB designers are faced with increasingly significant challenges for connecting the electronic components over longer distances.